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Heparin Antibody Panel

Justification

Up to 5 percent of patients receiving heparin develop heparin-induced thrombocytopenia (HIT), a life-threatening complication that can occur following exposure to heparin, regardless of the dose, schedule, or route of administration. The mortality rate can be as high as 20 percent; with early diagnosis, mortality rates have been reported as low as 2 percent. Ruling out HIT quickly can achieve both significant cost savings and experience better patient outcomes. This panel includes both Heparin Antibody screening and confirmatory tests to maximize clinical sensitivity and specificity.

Panel Component Tests

Heparin Antibody (HIT) Screen – PF4 (reflex to confirmation) Heparin Antibody (HIT) Functional Confirmation

STAT: < 24 hours (M-F)

WP-HIPA, ELISA

Draw Tube: Red Top

Sample Type: Serum

DRAW KITS AVAILABLE

Specimen Requirements

Sample Type Volume Required Minimum Volume Stability
PREFERRED Serum 1mL 0.5mL Room Temp.: 7 days
Refrigerated: 7 days
Frozen (-20C): 1 month
Frozen (-80C): 6 months
ALTERNATIVE Citrated Plasma 1mL - Frozen (-20C): 1 month
Frozen (-80C): 6 months
REJECTION CRITERIA Sample contamination; sample compromised
SPECIAL INSTRUCTIONS -

General Information

METHODOLOGY WP-HIPA, ELISA
STAT TAT < 24 hours (M-F)
STAT TAT Performance > 90% of results released in 24 hours
ROUTINE TAT < 24 hours (M-F)
ALTERNATIVE NAMES HIT Panel, Heparin-Induced Thrombocytopenia Panel, HIT Screen and Confirm, PF4 with confirmation, Serotonin Release Assay (SRA) equivalent
DESCRIPTION The wp-HIPA (washed platelet heparin-induced platelet activation) test is a quantitative, platelet activation assay capable of detecting clinically significant HIT antibodies. Washed platelet assays, such as the serotonin release assay (SRA) and heparin-induced platelet activation (wp-HIPA) are the reference or GOLD STANDARD methods for diagnosing HIT [1, 4]. Both assays are sensitive and specific for HIT because they ONLY detect antibodies that are capable of activating platelets [1, 3]. The wp-HIPA test is useful in the diagnosis of patients with weakly positive PF4 ELISA results (OD 0.4 – 1.0) and patients with low to intermediate 4T Scores[1, 5]. This test enhances specificity for HIT antibodies by testing 4 concentrations of heparin. This solid-phase ELISA detects the presence of anti-platelet factor 4 (PF4) antibodies in patient serum. Both optical density (OD) and interpretation are reported since OD correlates well with the likelihood of HIT. This test reflexes automatically to the wp-HIPA confirmation assay.
LIMITATIONS -
NORMAL RANGE Interpretation: Negative
ASSOCIATED TESTING -
REFERENCES

1. Linkins LA et al. Treatment and prevention of heparin-induced thrombocytopenia: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012; 141(2 Suppl):e495S-530S.

2. Multz AS et al. The Management of Suspected Heparin-Induced Thrombocytopenia in US Hospitals. Clin Appl Thromb Hemost. 2012; 20(1):68-72.

3. Warkentin TE et al. Laboratory testing for the antibodies that cause heparin-induced thrombocytopenia: how much class do we need? J Lab Clin Med. 200; 146(6):341-346.

4. Hess CN et al. Antithrombotic therapy in heparin-induced thrombocytopenia: guidelines translated for the clinician. J Thromb Thrombolysis. 2012; 34(4):552-561.

5. Cuker A et al. Predictive value of the 4Ts scoring system for heparin-induced thrombocytopenia: a systematic review and meta-analysis. Blood. 2012; 120(20):4160-4167.
SAMPLE REPORT Upon request
NEW YORK STATE APPROVED -

Test Codes

ORDER CODE P1181
CPT CODE 83520, 86022x3
LOINC CODE 73818-7, 50736-8, 77728-4